Method of heel forming and attaching



Get; 20, 1942.

A. E. USHAKOFF METHOD OF HEEL FORMING AND ATTACHING a 2 My 0 g 1 6 n 2. n v f w M m w Wl/{NTUA 1942. A. E. USHAKOFF 2,299,195

METHOD OF HEEL FORMING AND ATTACHING Filed NOV. 26, 1941 2 Sheets-Sheet 2 Patented Oct. 20, 1942 METHOD OF HEEL FORMING AND ATTACHING Alexis E. Ushakofl, Beverly, Mass, assignor to United Shoe Machinery Corporation, Flemington, N. J a corporation of New Jersey Application November 26, 1941, Serial No. 420,556

6 Claims.

This invention relates to heel forming and attaching, and more particularly to an improved method of forming and attaching a heel to a shoe in a single, continuous operation.

The object of the invention is to provide a new and improved method by the practice of which so called plastic heels, 1. e., heels made of plastic materials, may be quickly and securely formed and attached to shoes without requiring expensive or complicated machinery.

Hollow heels have been made by a novel method which consists in placing a heated, hollow blank of thermoplastic material in a heel-shaped mold and expanding the blank by fluid pressure into conformity with the inner wall of the mold. After the plastic material has set the heel is removed from the mold and is ready for attachment to a shoe in a separate operation. Such an improved method of making heels is disclosed and claimed in an application for Letters Patent of the United States, Serial No. 419,155, filed November 14, 1941, in the name of James F. Leahy.

According to the present invention a hollow, heel-shaped mold with a softened blank of plastic material therein is positioned in contact with the heel seat portion of a shoe, after which fluid pressure is applied to expand the blank, in a, single operation, into conformity with the mold and into interlocking relation with one or more recesses in, or projections upon, the heel seat. The apparatus required is simple and a plastic heel permanently attached to a shoe is obtained in a single operation, in contrast to the plurality of separate operations heretofore required, one, at least, of which required heavy, expensive machinery. Heel attaching, as a, separate operation, is eliminated, with a resultant substantial saving in cost of manufacture.

Although the full benefit of the process will not be obtained, it is, nevertheless, within the scope of the invention to attach a previously formed I or molded hollow heel to a shoe by softening at least a, portion of the heel, positioning it upon a prepared heel seat, and expanding the softened material by fluid pressure, causing it to flow into permanent interlocking contact with the discontinuous surface of the heel seat.

While any suitable fluid may be used for applying the pressure, it is convenient to employ compressed air for inflating the plastic heel blank and the process may, therefore, be regarded as a process of blowing a heel into permanent, interlocking contact with a shoe.

Referring to the accompanying drawings wherein the practice of the method is illustrated,

Fig. 1 is a perspective view of a hollow heel blank of thermoplastic material;

Fig. 2 is a view partly in elevation and partly in vertical longitudinal section illustrating the positioning of a heel mold and fluid pressure supplying nozzle on the heel seat portion of a shoe;

Fig. 3 shows the heel mold, heel seat of a shoe,

and partially expanded blank at an intermediate stage in the blank expanding operation;

Fig. 4 shows the heel blank fully expanded into conformity with the mold and into interlocking contact with the undercut surface of the heel seat;

Fig. 5 is a perspective view of the heel seat of a shoe provided with a discontinuous surface including an undercut recess and a plurality of partially driven nails;

Fig. 6 illustrates a heel attached to the heel seat prepared as shown in Fig. 5;

Fig. 7 is a perspective view of a heel seat prepared only by the partial insertion of a plurality of nails;

Fig. 8 shows a heel attached to the heel seat shown in Fig. 7;

Fig. 9 is a perspective view of a previously formed heel, a portion of the attaching face of which is softened;

Fig. 10 illustrates the attachment of the heel shown in Fig. 9 to the heel seat shown in Fig. 7; and

Fig. 11 illustrates one method of securing a toplift to a hollow, plastic heel.

In the illustrated procedure thereis provided a hollow blank or heel member 12 of thermoplastic material, such for example as plasticized cellulose acetate or plasticized cellulose acetate butyrate. This blank (Fig. 1) has a shape which depends to some extent upon the shape of the mold and has a hollow neck portion H. The thickness of the walls of the blank in any given locality is dependent upon the desired thickness of the walls of the finished heel and the extent to which the blank will be thinned or expanded at said given locality.

In preparation for forming and attaching the heel to a shoe, the heel seat of the shoe [6, which is shown as mounted upon a last I8, is provided with a discontinuous surface having overhanging portions with which the plastic material of the heel may be interlocked. This surface may be produced by forming an undercut recess 20 in the heel seat, as shown in Figs. 2, 3 and 4 or by partially driving a plurality of nails 22 in the heel seat, leaving their head ends projecting above the surface of the heel seat as shown in Figs. 7, 8 and 10, or by providing both the recess and the nails as shown in Figs. 5 and 6.

The shoe with the prepared heel seat is placed upon a shoe support 22 where it is held immovable by drawing down upon a rod 24 the flaring upper end 26 of which expands a sleeve 28 into close engagement with the interior of the last thimble 30 (see Fig. 2).

A hollow mold 32, the interior of which has th shape desired for the finished heel, is now accu'rately positioned upon the heel seat of the shoe with its hollow neck portion l4 surrounding a soft rubber nipple 40 which is mounted upon the delivery end of the nozzle 34. The nipple 4D has small openings 42 to permit the escape of air from the nozzle but the flow of compressed'air from the nozzle is-sufllcient to inflate the nipple somewhat and press it into air-tight contact with the neck portion I 4 of the blank. A series of spring fingers 44 are arranged around the outsideof the nozzle to engage the outer surface of the neck portion I4 of the blank.

The holddown 38 and the mold are now returned to their former positions, the mold engagaround the projecting nails or'into the undercut recess if such a recess is used, to produce a permanent interlocking engagement of the heel with the heel seat of the shoe.

In Fig.11. there is shown one way in which a toplift "may be satisfactorily attached to a heel of the type described above. In this case the tread end of the heel is cut of! square and the toplift is provided with a spring steel attaching-memtermlned. In this return movement, the hold- .down 38 engages the fingers 44, closing them tightly upon the outside of the neck portion l4 of the blank and holding it securely. The lower edge of the mold is formed as a thin edge 46 which is pressed into the heel seat of the shoe sufliciently to make tight contact therewith, and prevent the escape of thermoplastic material.

The compressed air is now admitted to expand the heel member l2 through the stage shown in Fig. 3 to the final condition illustrated in Fig. 4 where the finished heel conforms to the inner wall of the mold 32 and the portion 48 of the attaching face of the heel is expanded into permanent interlocking contact with the overhanging walls of the recess 20, thus securing the heel solidly to the shoe.

When the thermoplastic material has set, which it does very quickly, the holddown 38 and mold 32 are lifted away from the heel, permitting the fingers 44 to spring outward and release the neck portion I4 of the heel member so the nozzle 34 can be withdrawn therefrom. The attached heel is thus left with the projecting neck portion l4, which may be cut off flush with the tread face of the heel.

If the discontinuous surface of the heel seat is prepared as shown in Fig. 7, the mode of operation is otherwise exactly the same as that above described and the resulting product is as illustrated in Fig. 8; or both projecting nails and an undercut recess or reccesses may be used, as shown in Fig. 5, in which case the product will be as illustrated in Fig. 6, affording the maximum strength of attachment of the heel to the shoe.

Fig. 9 shows a preformed hollow heel which may be made of thermoplastic material by the method disclosed in the Leahy application mentioned above and which may be attached to a shoeby the method of my invention without the use of a mold. In this case, a portion 50 of the attaching face may be softened by heat, applied by a hotplate or otherwise, whereupon the heel may be placed directly upon the discontinuous ber, secured to the toplift by integral spurs 54, driven into the toplift, and having upwardly extending claws 56 which maybe heated and sprung into-theheel, whereupon their 'points will become embedded in the thermoplastic material, affording a permanent attachment of the toplift to the heel.

Having described the invention what is claimed as new, and desired to be secured by Letters Patent of the United States is:

1. The method of attaching a plastic heel member to a shoe, which comprises providing an overhang on the heel seat of a shoe, softening at least a portion of the heel member, positioning said member on the heel seat, expanding the softened material by fluid pressure, and causing it to flow into permanent interlocking contact with the overhang.

2. The method of attaching a hollow, plastic heel member to a shoe, which comprises forming an undercut recess in the heel seat of the shoe,

positioning a hollow heel blank, of which at least a portion is soft, upon the heel seat over the recess, and introducing fluid under pressure into the interior of the blank to expand a soft portion of the blank into the recess, whereby the heel member is permanently secured to the shoe.

3. The method of permanently attaching a hollow, plastic heel to a shoe, which comprises forming a projection on the heel seat of the shoe,

a plastic material in a hollow, heel-shaped mold,

positioning the mold-in contact with the heel seat portion of the shoe, and expanding the blank by fluid pressure into conformity with the mold and into permanent interlocking contact with the discontinuous surface of the heel seat.

5. The method of forming a heel and attaching it to a shoe, which comprises forming a recess in the heel seat of the shoe, placing a blank of plastic material in a heel-shaped mold, positioning the mold in contact with the heel seat portion of the shoe, and, in a single operation, expanding the blank by fluid pressure into conformity with the mold and into permanent interlocking relation with the'recess in the heel seat.

6. The method of simultaneously forming a heel and attaching it to a shoe, which comprises partially inserting nails into the heel seat of the heel seat of the shoe and held there while fluid pressure is created in the interior of the heel, preferably by introducing compressed airv as illustrated in Fig. 10. This internal pressure expands the softened portion 50 of the heel into intimate contact with the entire surface of the heel seat, causing the plastic material to flow shoe, placing a hollow blank of plastic material in a heel-shaped mold, positioning the mold in contact with the heel seat portion of the shoe and in a single operation, expanding the blank by fluid pressure into conformity with the mold and 

